FIG. 1 is a sectional view of a conventional chip packaging structure, in which a chip 10 is positioned on a chip pad 20 and a leadframe 30 is provided at each lateral side of the chip 10 to electrically connect with external elements. Each leadframe 30 includes a plurality of sequentially arranged terminal legs 301, which are connected to contacts on the chip 10 via gold wires 40. An insulating sealing material 50 is applied to enclose the chip 10 and thereby protects and locates the chip 10, the gold wires 40, and other internal elements in place.
It is known that electronic products in operation produce electromagnetic interferences (EMI), noises, including shot noise, flicker noise, surge noise, thermal noise, partition noise, etc., and high temperature. Most of the noises are produced due to electromagnetic interference and have adverse influences on the stability of the whole electronic system. It is difficult to completely overcome the electromagnetic interference, which must be, however, reduced to be lower than a standard value through proper circuit design or shielding and grounding structures for the electronic elements, so as to achieve the purpose of electromagnetic compatibility.
However, the above-described conventional chip packaging structure does not include any structural design for preventing electromagnetic interference to meet the high standard of electromagnetic compatibility required by current electronic products.